1. Field of the Disclosure
The present disclosure relates to an antenna device including an antenna element having a directivity toward a fixed direction.
2. Description of Related Art
In recent years, a mobile terminal typified by a mobile phone has become multifunctional and sophisticated, and the GPS (Global Positioning System) function has been installed in many mobile terminals. The GPS function allows for receiving radio waves that are transmitted from a plurality of GPS satellites and obtaining the current position of the terminal based on the reception signals.
On the earth's surface where the mobile terminal is used, the radio waves that are transmitted from the GPS satellites come from the sky. Therefore, the directivity of a GPS antenna provided in the mobile terminal needs to be aimed at the sky to increase the GPS-signal reception intensity.
However, there has been a growth in the opportunity to use the GPS function in the horizontal-holding state, such as viewing a map on an image screen, and the directivity attained at that time has also become important. That is, since the mobile terminal is used not only in the vertical-holding state where the mobile terminal is held so that the length direction thereof agrees with an up/down direction (an almost vertical direction), but also in the horizontal-holding state where the mobile terminal is held so that the length direction of the mobile terminal agrees with a horizontal direction, it is preferred that the directivity of the GPS antenna point in the zenith direction in either state.
According to known technologies, a mobile terminal including two GPS antennas and an acceleration sensor has been proposed as disclosed in Japanese Unexamined Patent Application Publication No. 2010-109522. In the mobile terminal, the inclination of the cabinet is sensed and a binary signal is output to operate a changeover switch making a changeover between the two GPS antennas, and the directivity of the GPS antenna, the directivity being aimed at the sky in the two states corresponding to vertical holding and horizontal holding by the changeover, becomes a reality.